How to build Blender with edited blender_icons?
Blender uses uncompress bitmaps for the icons, which are generated from the svg with a python script which depends on inkscape and blender. See this for details.

The basic workflow should be something like:


Edit svg
Run the python script in

blender/release/datafiles/blender_icons_update.py


If you are on linux, you can also run make icons instead.
Compile